U.S. Pat. No. 5,477,763 to Kullman shows a band saw blade having a plurality of unset teeth provided in recurring cycles, wherein each recurring cycle includes first and second groups of teeth, with the teeth of the second group being interspersed among the teeth of the first group. The teeth in the first group progressively decrease in height and increase in width from tooth to tooth. The teeth in the second group, on the other hand, are identical to each other, and the width of each tooth in the second group is greater than the width of any tooth of the first group. U.S. Pat. No. 6,276,249 to Handschuh et al. shows a band saw blade having a plurality of unset teeth provided in recurring cycles, wherein the teeth increase in height from tooth to tooth while simultaneously decreasing in width.
One of the drawbacks associated with these and like prior art band saw blades is that the cutting surfaces are defined by the relatively wide flat upper surfaces of the teeth. As a result, the blades may tend to wander laterally during cutting, particularly when cutting relatively large diameter workpieces, such as steel bars greater than about 15 or 20 inches in diameter or width. Thus, the blades may provide a crooked cut, or otherwise may not provide as straight a cut, or consistently as straight a cut, as otherwise desired. Another drawback associated with these and like prior art band saw blades is that the wider or outer teeth tend to take a greater cutting load than the inner or more narrow teeth. In addition, at higher feed rates, the wider or outer teeth tend to take progressively greater cutting loads. As a result, the tooth loading can be relatively unbalanced, which, in turn, can lead to premature failure, or shorter wear life than otherwise desired.
Aluminum titanium nitride (AlTiN) coatings are not believed to have been applied to band saw blades. AlTiN coatings are typically applied by physical vapor deposition to, for example, an underlying steel surface or substrate. If applied to a cutting tool, these coatings require the tool to be run at relatively high speeds and temperatures to achieve desired performance. In addition, these coatings require at break-in that the tool be run dry (i.e., without any lubricant) at relatively high speeds and temperatures in order to oxidize the coating and otherwise obtain the performance advantages thereof. Band saw blades, on the other hand, conventionally have been run at much slower speeds and feed rates than those required for AlTiN coatings. Moreover, conventional wisdom has tended to dictate running band saw blades at relatively slow band speeds and/or feed rates in order to improve wear and/or blade life. As a result, conventional band saw blades typically require a trade off between higher production rates (e.g., faster band speeds and/or feed rates) and wear or blade life. Thus, the longer the wear or blade life, the lower the production rates, and vice versa.
Accordingly, it is an object of the present invention to overcome one or more of the above-described drawbacks and/or disadvantages of the prior art.